PCM Diagnostics & Tuning - trading PCMs




View Full Version : trading PCMs


slamm69
06-15-2006, 07:21 PM
Can you switch a PCM from a 95TA to a 94Z28 just to check and see if the 94 PCM is bad?It stays in closed loop all the time and its throwing a shit load of codes.But will not read any changes in TPS,EGR,timing,and alot of other strange crap.Any help is appreciated.


fast377
06-15-2006, 07:39 PM
I think you can, but I can't remember if 95 was obd1 or 2? I know 94 was obd1.

slamm69
06-15-2006, 07:59 PM
I think you can, but I can't remember if 95 was obd1 or 2? I know 94 was obd1.
That should have been my question,are both of these years obd1's?If not what will happen if I try to switch them out?


horist
06-15-2006, 10:53 PM
OBDII was not mandated until 96 model vehicles... some manufacturers went to OBDII earlier than 96, and GM went to an OBDII style plugin in 95 I believe.... but the PCM should be OBDI

As for if the 94 and 95 PCMs are plug and play... I have no first hand experience w/pre LS1 PCMs so not sure on that answer..... but I can say with good certainty 95 was OBDI

as for what will happen if you try to switch them out.... I'm guessing the plug that attach to the PCM wouldn't fit... since OBDII has many more wires than OBDI

But as I mentioned... I don't know if the pinout and/or physical PCM are the same (but I would imagine they are.... 99-02 F-Body's were the same basic hardware/pinouts)

fast377
06-16-2006, 12:05 AM
OBDII was not mandated until 96 model vehicles... some manufacturers went to OBDII earlier than 96, and GM went to an OBDII style plugin in 95 I believe.... but the PCM should be OBDI


Thats what the deal was...I knew there was something different about the 95s.

slamm69
06-16-2006, 09:53 PM
Can someone local like a dealership or autozone test the PCM?

shaun
06-17-2006, 02:14 PM
i think the worse that will happen is it wont start. had the same thing on a 91 taurus and got a pcm from the salvage yard and it hooked up fine but it wouldent start

slamm69
06-21-2006, 08:35 PM
Does anyone know if a bad PCM will make the speed-o off?I checked the code in the glove box and checked the gears and both say I have 3.23's.But the speed-o is like 20 to 25 MPH fast at 70 MPH.I havent had the PCM checked yet I was just wondering if maybe someone else had had this problem?Would there be anyyhing else that might throw off the speed-o-meter?